Occupational contact urticaria and rhinitis caused by immediate allergy to palladium salts.

A 50-year-old previously healthy non-smoking laboratory technician, who had worked in catalyst research for 26 years, presented with recurrent urticaria on the hands and the face, and watery rhinitis associated with handling palladium salts at work. When exposed to fine dusts of dried and powdered mixtures containing the palladium nitrate salts Pd(NH3)4(NO3)2 and Pd(NO3)2, she immediately developed itchy facial erythema, which disappeared within hours. Occasional spillages of palladium salt solutions on the patient’s bare forearms caused immediate urticarial wheals to appear on the contact site. She also suffered from watery rhinitis and sneezing, and itching of the eyes, when she was exposed to fine dust of ground materials that contained palladium salts. She had no symptoms suggestive of asthma. She was symptom-free during leisure time and when she handled compounds of other metals, that is, platinum, rhodium, vanadium, and aluminium. Prick testing with common aeroallergens showed sensitization to tree pollens (Table 1). Prick tests with samples of two palladium compounds from the patient’s workplace gave positive results. Control prick tests with tetraamminepalladium(II) hydrogencarbonate (1% aq.) and tetraamminepalladium(II) nitrate (10% aq.) gave no positive reactions in 40 volunteers. In 3 of the volunteers, 2-mm wheals were observed with both palladium compounds, and were interpreted as signs of mild irritation.